Fans can achieve remote control switch, speed control, remote control can also be achieved in other household switches. Its main feature is the use of sub-transmission side ult
rasonic transmitter, no direction restriction, without power, and durability. Asia ultrasonic signal received by the piezoelectric buzzer V1 amplification, L, C4 frequency selection, and then amplified by V2, and the output pulse. Each operation, pinching at the transmitter, V2 collector outputs a positive pulse trigger signal, the decimal counter CD4017 count. Use CD4017s Q1, Q2, Q3 gear. When the fourth signal arrives, IC cleared. IC control transistor driven relays. Speed relay coil contacts to the former governor to change the fan speed. Slightly modified circuit can be expanded to 9 road.